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acylstab – an unique assay for evaluating the reactivity of acyl-glucuronide metabolites

3 December 2012

We at admescope are proud to be undisputed leaders in the field of reactive drug metabolites. Reactive metabolites are one of the main factors causing unexpected drug-induced toxicity and therefore their early screening is essential.

Glucuronide-conjugation is most commonly considered a detoxification route, but in the presence of carboxylic acid moiety in a parent or a metabolite, reactive acyl-glucuronide conjugates (AGs) can be formed. In the process called acyl migration the glucuronide moiety of acyl glucuronides can migrate leading to formation of several isomeric products. These conjugates can readily react with plasma and tissue proteins, and their chemical stability in various conditions is shown to correlate well with their toxicity.

With acylstab the acyl glucuronide conjugates are generated in human liver microsomes, after which the incubation is diluted with a buffer to a secondary incubation that is sampled to elucidate the half-life of the acyl-glucuronide. The results are compared to known and classified (safe/warning) control compounds to evaluate the possible associated risks. Use of UPLC/TOF-MS analysis results in very high quality separations between isomeric AGs formed via acyl migration reaction, and also differentiates disappearance by acyl migration or hydrolysis reaction. Thus with acylstab there is no need for synthesized acyl glucuronides.